Helped by its $67 billion mega merger with Wyeth, Pfizer (NYSE:PFE) reported second-quarter results on Tuesday that solidly beat Wall Street’s expectations and issued upbeat guidance, sending the drug giant’s stock jumping 4%.

Pfizer, the world’s largest drug maker, said it earned $2.48 billion, or 31 cents a share, last quarter, compared with $2.26 billion, or 34 cents a share, in the year-earlier period. Excluding one-time items, it earned 62 cents a share, exceeding estimates by a dime.

Revenue soared 58% last quarter to $17.33 billion, topping the Street’s view for $16.65 billion.

International revenue climbed 54% to $9.9 billion and U.S. revenue jumped 63% to $7.4 billion. Pfizer said its revenue was boosted by 5% due to currency fluctuations.

The markets cheered Pfizer’s better-than-expected results, bidding the pharmaceutical giant’s stock up 4..05% to $16.10. Even with those gains, however, the company’s shares were off by almost 15% on the year.

“During the quarter, Pfizer's more balanced global portfolio… generated strong performance in a period of notable worldwide economic uncertainty,” CEO Jeff Kindler said in a statement. “We continue to make solid progress on the Wyeth integration while we remain focused on delivering strong business performance.”

Pfizer, which finalized its deal to buy Wyeth in October, also reaffirmed its 2010 financial guidance, projecting revenue of $67 billion to $69 billion. Analysts had been projecting revenue of $67.3 billion.

Frank D’Amelio, Pfizer’s chief financial officer, said the company anticipates its 2010 non-GAAP EPS at the high end of its range of $2.10 to $2.20. Wall Street had been expecting EPS of $2.16.

Pfizer said its second-quarter biopharmaceutical sales soared 49% to $15.02 billion, primary care revenue rose 15% to $5.92 billion and specialty care revenue rose to $3.77 billion.

Sales of blockbuster cholesterol drug Lipitor rose 5% to $2.81 billion, while sales of Lyrica grew by 21% to $762 million. Viagra sales rose 16% to $491 million and Celebrex revenue was up 10% to $604 million.